The miniaturization of semiconductor devices and the like has been achieved using an exposure light source having a shorter wavelength in lithography. Artificially assisted self-assembling (AASA) method, in which the array of a pattern is controlled using a phase separation phenomenon of a block copolymer, is proposed as a method to obtain a fine polymer pattern with a high throughput at a lower cost (see, for example, U.S. Pat. No. 5,948,470).
A method of producing a recording medium using the obtained polymer pattern is also proposed (see, for example, JP-A 2002-279616 (KOKAI)). Although the polymer pattern is used as an etching mask, it becomes difficult to obtain a structure accurately corresponding to the phase-separated structure if the pattern size is reduced. The orderliness of the processed pattern is deteriorated by the generated size variation. Dyeing and dry etching steps are required, leading to increase in the number of process steps and in cost.